Variable resistance and indicator therefor



Oct. 28, 1947. R. J. BEAGLES VARIABLE RESISTANCE AND INDICATOR THEREFORFiled May 25, 1944 Patented Oct. 28, 1947 UNITED STATES PATENT OFFICEVARIABLE RESISTANCE AND INDICATOR THEREFOR 1 Claim.

The present invention relates to a variable rcsistance or rheostatembodying an arm adapted for swinging movement around a spirally formedresistance element, and has for its primary object to provide a slidingcontact carried by the arm and adapted to travel on the edge of theresistance element to any selected point along the length thereof and toprovide indicating means by means of which the amount of resistance inthe circuit can be determined.

An important object of the present invention is to provide a variableresistance of this character arranged in compact form and of simple andpractical construction, relatively inexpensive to manufacture andotherwise well adapted for the purposes for which the same is intended.

Other objects and advantages reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawing forming part hereof, wherein likenumerals refor to like parts throughout, and in which:

Figure 1 is a top plan view with parts broken away and shown in section.

Figure 2 is a fragmentary sectional view taken substantially on a line2-2 of Figure 1.

Figure 3 is a transverse sectional view through .the arm and showing thesliding contact mounted thereon.

Figure 4 is a bottom enlarged plan view of the contact.

Referring now to the drawing in detail, wherein for the purpose ofillustration I have disclosed a preferred embodiment of the invention,the numeral 5 designates an annular base of insulation material having ashaft 6 journaled centrally therein and having its upper surface formedwith a spiral groove 1 in which the convolutions are spaced apart and inwhich the resistance strip 8 is positioned with the upper edge of thestrip projecting above the surface of the base.

Secured to the shaft 6 is a collar 9 having an arm ll] extendingradially therefrom overlying the upper edges of the strip 8.

A slide II is freely mounted on the arm to the under side of which issecured an ovalshaped contact member I2 of resilient material having apair of downwardly struck tongues 13 at its opposite side edges disposedin wiping contact with the opposite side edges of the resistance strip8. The front and rear ends of the tongues I3 are bent outwardly, asshown at M, to prevent interference with the strip.

The arm I0, the slide H and the resistance strip 8 are enclosed within atransparent cover I having its edges telescoping over the side edges ofthe base 5, the cover being supported in an elevated position above thearm. The under side of the cover 15 is marked with calibrations dividingthe resistance strip into a suitable number of equal spaces to designatethe ohm resistance, as indicated through the position of the slidingcontact on the resistance strip.

To the upper end of the shaft 6 is secured the knob I! by means of whichthe shaft may be rotated and the arm l0 swung around the resistancestrip.

The shaft 6, arm [0, slide l l and contact member with its tongues 13are formed of conductive material and circuit Wires may be attached tothe shaft and to the end of the outer convolution of the resistancestrip to include the rheostat in the circuit.

It is believed the details of construction and the manner of operationand advantages of the device will be readily understood from theforegoing without further detailed explanation.

Having thus described the invention, what I claim is:

A variable resistance of the class described and of a type including aspiral resistance element and a manually operable arm mounted in aposition overlying the resistance element for swinging movement over theelement, a slide carried by the arm, a ring-shaped substantial ovalspring contact member attached at its outer periphery to the under sideof the slide, and downwardly struck tongues on opposite side edges ofthe contact in wiping engagement with opposite sides of the resistanceelement, said tongues extending from a portion diametrally opposite theportion attaching the contact to the slide.

RUFUS J. BEAGLES.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 480,893 Weston Aug. 16, 18921,152,913 Sagle Sept. 7, 1915 170,272 Kelley Nov, 23, 1875 1,320,119Brown et a1. Oct. 28, 1919 1,450,919 Harris Apr. 10, 1923 1,473,915Martin Nov, 13, 1923 1,785,779 Lauter Dec. 23, 1930 1,921,441 TempletonAug. 8, 1933 2,085,404 Vollenbroek June 29, 1937 2,361,010 Cary et a1Oct. 24, 1944 FOREIGN PATENTS Number Country Date 232,476 Great BritainApr. 23, 1925

